In August 2008, just after graduating from Boston College and a month after the death of his father, NBC News hired Russert as a correspondent covering youth issues as part of its coverage of the 2008 presidential election. He was assigned to cover both the Democratic and Republican conventions.[7][8] His election day report, which explored the impact of Barack Obama’s win on young people, contributed to NBC’s News & Documentary Emmy award for its 2008 Election Night coverage.[9]

He has openly acknowledged that critics in the media, including some colleagues, have leveled accusations of unqualified nepotism, because of both his father's position at NBC and his mother's position as a Vanity Fair correspondent, given that he had virtually no professional experience at the time of his hiring. He stated that he merely attempts to ignore it.[10]

From May 2009 to July 2016, he worked for NBC News on Capitol Hill as a Congressional correspondent covering the House of Representatives. He made headlines in 2010 when he received a public apology from Rep. Charlie Rangel (D-NY), who was at the time serving as House Ways and Means Committee Chairman. Congressman Rangel had criticized Russert’s aggressive questioning over an ethics report that showed Rangel’s fiscal indiscretions and illegal donation solicitations, but then reversed his stance and apologized to Russert instead.[11]

In February 2012, Russert made his primetime debut on NBC's Dateline with "Conviction," which examined whether the 1998 murder conviction of Jon-Adrian Velazquez was justified or whether Velazquez was wrongly sentenced to life imprisonment for a murder he didn’t commit.[13] The episode was nominated for a News & Documentary Emmy award for Best Report in a News Magazine.[14]

Russert has claimed that the American media is biased against people of religious faith, going so far as to suggest that it treats them with a certain degree of snark, labeling them as "puritanical" and "not understanding of others or of different viewpoints", which in his view is lazy and contributes to "[feeding] the snickering masses."[15]

Russert hosted The Briefing, a web-only show on msnbc.com; he has said he likes to think of it as a "younger man's Charlie Rose".[16]

Russert suddenly resigned from NBC in July 2016, saying he needed to evaluate his career opportunites.[2]

Russert is involved with charitable causes that were supported by his late father.[17] On April 20, 2010, he took the role of emcee of the Boys & Girls Club of Greater Washington's annual Congressional dinner, which was renamed after his father.[18]

He has told POLITICO that, as a sports junkie, he makes sure to watch ESPN’s SportsCenter and College GameDay and NBC’s Sunday Night Football. He also told POLITICO that his favorite watering holes in D.C. are Ireland’s Four Fields in Woodley Park because its bartenders “pour a great Guinness, and on any given night you can catch some first-rate live music.” He also likes Billy Martin’s Tavern in Georgetown because “you never know who you will be seated next to at the bar. It could be a cop coming off his shift, a college student or even a congressman.”[19]

Russert is a member of the Buffalo Fan Alliance Board, an organization committed to keeping the Buffalo Bills within the city of Buffalo, New York, the hometown of his father. In 2013, he said “I honestly think being a Bills fan is something that’s passed down into your blood. My grandfather was a die hard Bills fans and he passed it on to my dad. I was given a Buffalo Bills jersey when I was probably two years old, so there was really never any doubt that I’d be a Bills fan.”[21]

In 2014, he penned an introduction, dedicated to his father, for the tenth anniversary of his father's bestselling book Big Russ and Me.[22]